Implement safe cracking logic and setup development environment

- Added a new `main.cpp` file with logic to parse dial rotations from a file and execute safe cracking based on the parsed data.
- Introduced a `DialRotation` struct to represent the direction and distance of dial rotations.
- Implemented `parseRotations` function to read and parse input from a specified file, returning a vector of `DialRotation` or an error message.
- Created `executeSafeCrack` function to process the dial rotations and print the current state of the dial.
- Added `.clang-format` and `.clang-tidy` configuration files for code formatting and linting.
- Set up a Dockerfile for a development container with necessary tools and dependencies.
- Configured VS Code settings and tasks for building, formatting, and running clang-tidy.
- Added a script to run clang-tidy on the source files, ensuring code quality.

.clang-format

@@ -0,0 +1,3 @@
+BasedOnStyle: Google
+IndentWidth: 4
+ColumnLimit: 120

.clang-tidy

@@ -0,0 +1,4 @@
+Checks: '-*,modernize-*,readability-*,bugprone-*,performance-*'
+WarningsAsErrors: ''
+HeaderFilterRegex: '.*'
+FormatStyle: file

.devcontainer/Dockerfile

@@ -0,0 +1,23 @@
+FROM xianpengshen/clang-tools:21
+
+# Install development tools (cmake, ninja, build essentials)
+USER root
+RUN apt-get update \
+   && apt-get install -y --no-install-recommends \
+   cmake \
+   ninja-build \
+   build-essential \
+   git \
+   python3 \
+   python3-pip \
+   ca-certificates \
+   && rm -rf /var/lib/apt/lists/*
+
+# Create workspace folder (VS Code devcontainer convention)
+ARG WORKSPACE_FOLDER=/workspaces/aoc25
+RUN mkdir -p ${WORKSPACE_FOLDER} && chown -R root:root ${WORKSPACE_FOLDER}
+WORKDIR ${WORKSPACE_FOLDER}
+
+ENV SHELL=/bin/bash
+
+CMD ["bash"]

.devcontainer/devcontainer.json

@@ -0,0 +1,20 @@
+{
+  "name": "aoc25-clang21",
+  "build": {
+    "dockerfile": "Dockerfile"
+  },
+  "workspaceFolder": "/workspaces/aoc25",
+  "workspaceMount": "source=${localWorkspaceFolder},target=/workspaces/aoc25,type=bind,consistency=cached",
+  "settings": {
+    "C_Cpp.default.compilerPath": "/usr/bin/clang++-21",
+    "C_Cpp.default.intelliSenseMode": "linux-clang-x64",
+    "clang-format.executable": "/usr/bin/clang-format-21"
+  },
+  "extensions": [
+    "ms-vscode.cpptools",
+    "ms-vscode.cmake-tools",
+    "llvm-vs-code-extensions.vscode-clangd",
+    "xaver.clang-format"
+  ],
+  "postCreateCommand": "cmake -S . -B build || true"
+}

.vscode/settings.json

@@ -0,0 +1,9 @@
+{
+    "editor.formatOnSave": true,
+    "C_Cpp.default.configurationProvider": "ms-vscode.cmake-tools",
+    "cmake.configureOnOpen": false,
+    "cmake.generator": "Ninja",
+    "clangd.arguments": [
+        "--compile-commands-dir=build"
+    ]
+}

.vscode/tasks.json

@@ -0,0 +1,33 @@
+{
+  "version": "2.0.0",
+  "tasks": [
+    {
+      "label": "CMake: Configure",
+      "type": "shell",
+      "command": "cmake -S . -B build -DCMAKE_EXPORT_COMPILE_COMMANDS=ON",
+      "problemMatcher": []
+    },
+    {
+      "label": "CMake: Build",
+      "type": "shell",
+      "command": "cmake --build build -- -j",
+      "problemMatcher": []
+    },
+    {
+      "label": "Clang-Format: Format Workspace",
+      "type": "shell",
+      "command": "bash -lc \"find . -name \"*.cpp\" -o -name \"*.hpp\" -o -name \"*.h\" | xargs -r clang-format -i\"",
+      "problemMatcher": []
+    },
+    {
+      "label": "Clang-Tidy: Run",
+      "type": "shell",
+      "command": "./scripts/run-clang-tidy.sh",
+      "presentation": {
+        "reveal": "always",
+        "panel": "shared"
+      },
+      "problemMatcher": []
+    }
+  ]
+}

CMakeLists.txt

@@ -1,4 +1,9 @@
 cmake_minimum_required(VERSION 3.10.0)
+
+# Set compilers before project() to ensure they're used
+set(CMAKE_C_COMPILER /usr/bin/clang-21)
+set(CMAKE_CXX_COMPILER /usr/bin/clang++-21)
+
 project(aoc25 VERSION 0.1.0 LANGUAGES C CXX)
 
 # Per-day subprojects (example: day1)

day1/CMakeLists.txt

@@ -1,2 +1,11 @@
 add_executable(day1 main.cpp)
-set_target_properties(day1 PROPERTIES CXX_STANDARD 17 CXX_STANDARD_REQUIRED ON)
+set_target_properties(day1 PROPERTIES CXX_STANDARD 23 CXX_STANDARD_REQUIRED ON)
+# Use GCC 15's libstdc++ with Clang 21
+target_compile_options(day1 PRIVATE --gcc-toolchain=/usr)
+
+add_custom_command(TARGET day1 POST_BUILD
+    COMMAND ${CMAKE_COMMAND} -E copy
+    ${CMAKE_CURRENT_SOURCE_DIR}/day1_input
+    $<TARGET_FILE_DIR:day1>/day1_input
+    COMMENT "Copying day1_input to build directory"
+)

day1/main.cpp

@@ -1,5 +1,76 @@
 #include <iostream>
+#include <fstream>
+#include <vector>
+#include <expected>
+#include <print>
 
-int main(int, char**){
+struct DialRotation {
-    std::cout << "Hello, from aoc25 day1!\n";
+    char direction;
+    int distance;
+};
+
+auto parseRotations(const std::string& filename) -> std::expected<std::vector<DialRotation>, std::string> { 
+    std::ifstream inputF {filename};
+    
+    if (!inputF){
+
+        return std::unexpected{"Some file open error.\n"};
+    }
+    std::vector<DialRotation> dialRotations{}; 
+    DialRotation curDial{};
+    while ( inputF >> curDial.direction >> curDial.distance)
+    {
+        //std::println("{} : {}", curDial.direction, curDial.distance);
+        dialRotations.push_back(curDial);
+    }
+
+    return std::move(dialRotations);
+}
+constexpr int dialStart = 50;
+constexpr int maxDial = 100 ;
+
+auto executeSafeCrack(const std::vector<DialRotation>& dialRotations){
+    int dial {dialStart};
+    int countZero {};
+    for (const auto& curDial : dialRotations){
+        if(curDial.direction == 'L'){
+            dial -= curDial.distance % maxDial;
+            if (dial < 0){
+                dial += maxDial;
+            }
+        }
+        else{
+            dial += curDial.distance % maxDial;
+            if (dial > maxDial - 1){
+                dial -= maxDial;
+            }
+        }
+
+       
+        std::println("{} : {:3}, Dial now at: {:5}", curDial.direction, curDial.distance, dial); 
+        if (dial == 0){
+            countZero++;
+        }
+        if (dial < 0){
+            break;
+        } 
+        if (dial > maxDial){
+            break;
+        }
+    }
+    std::print("Zeros: {}", countZero);
+}   
+
+auto main(int, char**) -> int {
+    std::cout << "Hello, from aoc25 day1!!\n";
+    auto retval = parseRotations("day1_input");
+
+    if(retval)
+    {
+        executeSafeCrack(*retval);
+    }
+    else{
+        std::print("{}\n", retval.error());    
+    }
+    return 0;
 }

scripts/run-clang-tidy.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+set -euo pipefail
+BUILD_DIR=build
+if [ ! -f "${BUILD_DIR}/compile_commands.json" ]; then
+  echo "compile_commands.json not found; running cmake configure..."
+  cmake -S . -B "${BUILD_DIR}" -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
+fi
+if ! command -v clang-tidy >/dev/null 2>&1; then
+  echo "clang-tidy not found in PATH"
+  exit 1
+fi
+
+# Prefer files tracked by git; fallback to find
+if git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
+  FILES=$(git ls-files '*.cpp' '*.cxx' '*.cc' '*.h' '*.hpp' || true)
+else
+  FILES=$(find . -iname "*.cpp" -o -iname "*.cc" -o -iname "*.cxx" -o -iname "*.h" -o -iname "*.hpp")
+fi
+
+if [ -z "${FILES}" ]; then
+  echo "No source files found for clang-tidy"
+  exit 0
+fi
+
+for f in ${FILES}; do
+  echo "Running clang-tidy on ${f}"
+  clang-tidy "${f}" -p "${BUILD_DIR}" || true
+done